Induction-motor construction.



H. F. ELSHOFP. INDUCTION MOTOR CONSTRUCTION.

APPLICATION FILED FBB.7,1906.

9'1 1,4;81 Patented Feb. 2, 1909.

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HENRY F. ELSHOFll, 0F NORWOOD, OHIO, ASSIGNOR TO THE FACTURING COMPANY, A CORPORATION OF OHIO.

INDUCTION -MOTOB CONSTRUCTION.

Specification of Letters Patent.

Patented Feb. 12, 1909.

Application filed February 7,1906. Serial No. 299,994.

To all whom it may concern:

, Be it known that I, HENRY F. Ersrrorr, citizen of the'United States, residing at N orwood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Induction-Motor Conclear, and exact specification. U

, My invention relates toinduction motors and more particularly to the means for connecting the conductor bars to the short circuiting rings in rotors having, squirrel cage windings. One of the objects of my invention is to e a connection for the conductor. bars andthe rings which will be in xpensive, simple and efi'eotive, and which will crmit: the parts of the .rotor to be assembled more easily and quickly. .A- further ob ect 1s to provide aconnection between the bars and the short-circuiting rinrswherebylthe heating of the conductors of the rotor is lessened and which ,will permit a more efiectivecooling of the stator coils.

In carrying out my invention I connect the ars to the short-'circuiting rin'rs byme'ans of tubular members such as hollow rivets or bolts. 7 B means of this oonnectionn'ot only can the liars be securely attachedto the short-circuiting rings without the expenditure of as much time and labor, as was formerly bolts permit a circulation of cooling, air current through theL-ends of the bars and the short circuitin'g IlIljYS, ,whereby the ends of the conductors and the rings are maintained at a more uniform low temperature, and the end-turns of the stator coils which extend beyond the stator eoreadiacent the ends of the conductor bars and the shOrt-circhiting rin s are cooled by thej air currents.

Iy invention furthermore consists in the details of construction and combinations of elements describ ed .in the specification and set forth in the appended claims.

For a betterunderstanding of my invention, reference is had to. the accompanying drawings, in Whioh Figure 1 is an end view of the rotor, parts being broken away and in section for the sake of clearness; Fig. 2 is a section through a portion of an induction motor showing one end of a bar connected to a. short-circuiting ring bilmeans of a single rivet; Fig. 3 1s a section t ough a portion of an inducfollowing is a full,

I prefer to required, but the hollow rivets or joint.

tion motor showing the 'use of two rivets for connecting one end of a bar to a short-circuiting ring; and Fig. 4 is a plan view of a portion of a short-circuiting ring and a pair of conductor bars joined together, in accordance with my invention.

Referring now to the figures of the drawing, have shown at 10 the shaft of the machine on which is mounted the spider 11, which consists'essentially of a hub 12, radial arms 13 and rim 14 on which is mounted a laminated core 15. The core is provided with the usual slots .in which are mounted conductor bars 16, which extend beyond each side of the'core as in the usual manner.

Theends of the conductor bars at each side of the mac care connect-ed together by a short-circuitmg ring 11. The rings in this caseare of the shape of angle sectlons, each avmg onevertical portion 18 at right angles to the axis of the machine and a circular ring portion 19 at right angles to the vertical portion. Each co ductor bar is connected to the short-circuiting ring by means of one or more tubular members of conducting material such as hollow bolts or rivets 20. employ hollow rivets having their endsbeaded or spunas show at 21. In small machinesa sin 1e rivet or boltat each end of each bar will e sufiicient. This construction is shown in Fig. 2. In larger machines, it may be necessary to provide two, or even more bolts or rivets for each end of each bar to provide a'sufficiently strong In Fig. 3 is shown a portion of a motor in which-the ends of the bars are each connected to a ring-by two rivets or bolts.

drawing the s okes of As is clear from the the spider are provided with fan-b ades 22 which support the short-circuiting rings, the vertical portions 18 of the rings engaging notched portions of the blades. I prefer to arrange the hollow rivets radially with respect to the axis of the rotor but my invention is not limited to such arrangement.

Surrounding the rotor is the stator, a portion of the laminated core of which is shown at 23. The stator is provided with the usual alternating current winding or windings having end-turns 24 which extend beyond the core and which surround the ends BULLOCK ELECTRIC nA-NU of the conductor bars and the short-circuitmg rings.

t is seen that the connection is strong and durable and the parts can be quickly assembled. The air currents created by the t tor conductor bars, a ring for short-circuitmg fan-blades are driven through the hollow I said bars, and means for connecting the bars rivets or bolts, not only cooling the bars and the rings but also cooling the end-turns of the stator coils. This is a distinct advantage forthe reason that, uith the use of solid rivets or bolts, the ends of thebars and the rings frequently become very hot on account of the high resistance of defective joints, and as the temperature rises the rivets or bolts expand in the direction of their length causing the resistance and the temperature of such joints to rise still further. Also rith the previous constructions, the cooling of the stator coils by the rotor fans was seriously interfered rith by the short.- circuiting rings.

I aim in my claims to cover all modifications r hich do not involve a departure from the spirit and scope of my invention;

What I claim as new and desire, to secure by Letters Patent is:

1. In an induction motor, the squirrel cage rotor having a plurality of conductor bars, a 5 conductor ring at each end of the rotor for t short-circuiting the bars, and means comprising radial tubular members forconnect-- mg the bars and the rings.

2. In an induction motor, a plurality of rotor conductorbars, a conducting ring at each end of the rotor for short-circniting the bars, and means comprising radial hollow rivets for connecting the bars and the rings.

3. In an induction motor, astator, a rotor having a plurality of conductorbars, a shortcircuiting ring for the bars at each end of the rotor, tubular members for connecting the bars and the short-circuiting rings, and fanblades on the rotor between the shaft'and the rings.

4. In an induction motor, a stator, a rotor having a plurality of conductor bar s, a sliortcircuiting ring for the bars at each end of the rotor, noll'ow rivets tor connecting the bars and short-circuiting rings, and fambladc's on the rotor between the shaft and the rings.

5. In an induction motor, a stator, a rotor having a plurality of conductor bars, a ring at each end of the rotor for short-circuiting the bais, and one or more radial hollow rivets for connecting each end of a bar to a ring.

6. In an induction motor, a plurality of r0- and rings, each of said connecting means having a substantially radial opening therethrough permitting a circulation of air.

7. In an induction motor, a stator having windings the end-turns of which extendbeyond the stator core, a rotor having a pinrality of conductor bars withends extending beyond the rotor core adjacent the end-turns of the stator coils, short-circuiting rings for the conductors at each side of the rotor core, hollow rivets for securing the endsoi' the conductor bars to the short-circuiting hin s, and fan-blades on the rotor within the cofi ductor bars.

8. A rotor comprising a core, a winding on said core, consisting of. bars of conducting material and short-circuiting rings at the ends of the bars, and tubular members for electrically connecting said bars to the rings,

said tubular members being arranged radially with respect to the rings, whereby radial circulation of air is permitted through said tubular members.

9. A rotor comprising a core, a Winding on said core consisting ot' bars of conducting material, short-circuiting rings at the ends of.

' t-or is in operation.

10. In an induction motor, a stator comprising a core and windingsthereon, a squirrel cage rotor comprising a core and a winding consisting'of a plurality of conductor bars with ends extending beyond the rotor core, short-circuiting rings for the conductor bars, and radial tubular members for-electrically connecting said bars to the rings, said tubular rings being adjacent the end turns of the stator winding and fan blades carried by the rotor whereby air can be formed through the tubular members cooling the connections and the stator coils.

In testimony whereof I affix my, signature, in the presence of two Witnesses.

HENRY F. ELSHOFF. I'Vitnesses:

ARTHUR F. Kwrs, FRED JIKINsEY; 

